NuCypher KMS is a decentralized Key Management System (KMS) that addresses the limitations of using consensus networks to securely store and manipulate private, encrypted data. It pro- vides encryption and cryptographic access control, performed by a decentralized network, leveraging proxy re-encryption. Unlike centralized KMS as a service solutions, it doesn’t require trusting a service provider. NuCypher KMS enables sharing of sensitive data for both decentralized and cen- tralized applications, providing security infrastructure for applications from healthcare to identity management to decentralized content marketplaces. NuCypher KMS will be an essential part of decentralized applications, just as SSL/TLS is an essential part of every secure web application.